"We treat each other with respect and we have a great working relationship. Personal relationships are not [...] an issue," he explained. "We don't have them and we won't."

The question about sexual relations in space came after an April mission that put a record four women in orbit--the most women in space ever. Three women aboard the Discovery joined another woman and four men aboard the International Space Station.

Take a tour inside the International Space Station via the video below. Even if NASA's policy were not in place, the close quarters could make intimacy difficult...